   [f source {:keys [format] :as opts}]
   (if-let [format (or format (infer-format-of source))]
     (f source (assoc opts :format format))
-    (throw (IllegalArgumentException. (str "Please specify a format, it could not be from the source: " source)))))
+    (throw (IllegalArgumentException. (str "Please specify a format, it could not be inferred from the source: " source)))))
 
 (defmethod read-dataset-source Dataset [ds opts] ds)
 

  "Adds metadata about where the dataset was loaded from to the object."
  (cond
    (#{String File URI URL} (class data-source)) (with-meta output-ds {:grafter.tabular/data-source data-source})
    :else (with-meta output-ds {:grafter.tabular/data-source :datasource-unknown})))

(defmulti ^:no-doc read-dataset*

                                 [columns-or-f data-seq])
         full-data (fill-gaps-with-nil rows column-headers)]
     (-> (inc/dataset column-headers full-data)
         (with-meta (meta data))))))

(defn dataset?
  "Predicate function to test whether the supplied argument is a
